Offering a sacrifice involves a careful division of the animal, separating the mundane from the sacred. The act of bringing the peace offering establishes a clear boundary between the portions meant for human consumption and those dedicated entirely to God. When the priest places the selected portions on the altar fire, he must gather all the designated parts and burn them at exactly the same time, rather than placing them into the flames piece by piece [פירושי רד צ הופמן]. This unified action gathers two distinct types of offerings: the actual fats, which are strictly forbidden for human consumption, and other internal parts, such as the tail and kidneys. Though physically different, they are grouped together because they share the identical requirement of being burned on the altar [ביאור יש״ר].
A sweeping rule governs this process: every piece of fat within the animal is exclusively dedicated to God and must be consumed by the altar's fire [אבן עזרא, ביאור שטיינזלץ, אילת השחר]. This total dedication emphasizes that the fat belongs solely to Him, creating a sharp contrast with the rest of the meat, which is shared between the priests and the people bringing the offering. Consequently, it is strictly forbidden for anyone to eat the fat [רלב״ג, אבן עזרא]. This absolute dedication also clarifies that the fat itself is the primary essence of the sacrifice. The severe penalty for eating applies specifically to the fat, and not to the other internal organs that happen to be burned alongside it [ביאור יש״ר].
The primary approach among commentators is that this absolute dedication introduces the strict laws of misusing sacred property. A peace offering is generally considered a sacrifice of lesser sanctity, meaning the animal technically belongs to the person bringing it. However, the moment the animal's blood is dashed against the altar, a profound shift occurs. The fats instantly become holy to God. From that exact moment onward, deriving any ordinary, secular benefit from them constitutes a severe violation of sacred property [תורה תמימה, רש ר הירש, אדרת אליהו, מלבי״ם].
The inclusive requirement regarding the fat serves to expand the laws of the altar even further. Some commentators explain that this broad inclusion teaches that the fats of other types of sacrifices, such as the animal tithe and the Passover offering, must also be burned on the altar. Others derive more complex legal principles regarding the severity of the eating prohibition, concluding that an additional layer of prohibition can take effect on top of an existing one when dealing with these sacred fats [מלבי״ם, פירושי רד צ הופמן, תיבת גמא].